1. Field of the Invention
The present invention relates to a fluid flow regulator. More particularly, the present invention relates to an ink flow regulator and a writing pen having an ink flow regulator.
2. Description of Related Art
U.S. Pat. No. 4,382,707 to Anderka discloses a writing pen having a cylindrical body supporting a writing tip at an anterior end and an ink reservoir at a posterior end. The anterior end of Anderka's cylindrical body includes inner and outer pressure equalization chambers having interconnected posterior ends. Anderka's outer pressure equalization chamber includes an anterior communication to ambient air. Anderka specifically discloses passages having noncapillary rectangular cross-sections.
U.S. Pat. No. 4,671,692 to Inaba also discloses a writing pen having an ink flow regulator. Inaba's regulator has a plurality of circumferential fins that cooperatively define a labyrinth of separate chambers which are sequentially filled by excess ink. To ensure excess ink does not flow directly from the reservoir to the air vent located near the tip, Inaba's fin spacing is smallest near the reservoir and increases progressively, or in stages, toward the tip. Similar to Anderka, Inaba's chambers also have a rectangular cross-section that is not favorable to capillary attraction.